Previously, lastTimestamp was advanced before processing messages.
If processMessage threw an error, those messages would be skipped
on the next tick since the timestamp had already moved past them.
Now we advance lastTimestamp after each message is successfully
processed (or after catching an error), ensuring no messages are
lost on retry.
https://claude.ai/code/session_01LgHSAs9XbcvZckCe8xPipj
